1. Field of the Disclosure
Generally, the present disclosure relates generally to piping manifolds used for transferring liquid chemical and/or petroleum-based products between facilities used for storing the products, such as tanks, vessels, drums, and the like, and vehicles using for transporting the liquid products, such as railroad cars, trucks, barges, ships, and the like. More specifically, the present disclosure relates to the pressure-retaining piping components used to facilitate process liquid flow between the multiple pipes making up a piping system and/or piping manifold used for directing flow from multiple sources to multiple destinations.
2. Description of the Related Art
Many different types of pressure-retaining components are typically used in the piping systems designed for transferring chemical and/or petrochemical products to and from multiple product sources and multiple product destinations. For example, a variety of commonly available piping components, such as pipes, fittings, flanges, valves, vessels, drums, tanks, and the like, in an assortment of different sizes, arrangements, and materials, may be used under various process conditions to facilitate these product transfer activities.
In an effort reduce the overall complexity and other attendant problems associated with the use of multiple pipes, multiple flexible lines, and/or multiple hoses—as may commonly be employed in many loading/transfer systems—some applications may utilize large piping manifold assemblies, each of which may include several different inlet lines and several different outlet lines, many of which may be shop fabricated and skid-mounted for transportation to the transfer facility site. Furthermore, current design approaches for skid-mounted transfer manifolds have led to more and more compact assemblies, which generally permit more piping headers and valves to be used in the same or even smaller volume, thus allowing more equipment to be included on a given skid size, while still providing a manifold system that can be economically transported.
Moreover, these piping manifolds that are typically made up of numerous inlet and outlet lines may be designed to handle (i.e., transfer and/or load) multiple different chemical and/or petrochemical products on a substantially continuous basis. Therefore, the amount of time that may be available to perform commonly required maintenance activities, such as inspection, repair, replacement, and the like, may be substantially reduced, as manifold downtime may translate directly into lost loading/transfer capabilities, and commensurately into lost revenues. In general, then, there is a need to reduce the amount of time that may otherwise be required to perform routine maintenance on the equipment making up these types of loading and/or transfer manifolds, such as, for example, valve replacement and the like, while still ensuring that overall quality concerns are still addressed. However, in many applications, due to the increasingly compact manifold designs currently being implemented, easy access to equipment for inspection and/or removal may be significantly impacted, thereby translating directly into additional time that may be required to perform the necessary maintenance.
For example, in some system designs wherein a large number of valves are used to control the flow through the piping manifold, the valves may be installed in the manifold with a fitting make-up—e.g., flange-to-flange or seal face-to-seal face—to adjacent piping components. Such a fitting make-up is commonly not a problem in shop fabricated, skid-mounted manifolds, as the valve installation may be executed as part of a well-planned fabrication sequence so as to avoid clearance and/or space problems. However, efforts to remove a single valve randomly located in a large skid may be problematic for several reasons. First, with fitting make-up, the possibility of causing seal face damage to the valve, the mating piping components, or both, may significantly increase, as there may be very little space to handle and maneuver the valve into and/or out of position when being installed and/or removed. Such seal face damage may lead to connection leakage during manifold operation, a situation that may of itself require additional manifold maintenance activities to be performed. Furthermore, the compact nature of the piping manifolds in general may lead to assemblies that are, overall, very stiff—in other words, not very flexible. Any attempts which may be made to “cold spring” the piping components so as to allow more space to remove a valve that is being taken out of service, or to fit up a replacement valve, may lead to damage of the adjacent equipment, leakage at pressure joints, or both. Moreover, many operators may specifically prohibit the use “cold springing” during valve installation.
Accordingly, there is a need to provide a robust design for the pressure-retaining piping components and other equipment used in the fabrication of piping systems and/or piping manifolds that is also maintenance-friendly, so as address or reduce at least some of the problems outlined above.